Zonal centrifuge rotors

ABSTRACT

Zonal centrifuge rotors are disclosed which have a core that cannot be passed into the chamber of the bowl through an axial port in its top wall that is preferably an integral part of a bowl. Each core includes a hub and fins having detachably engaged portions and dimensioned to pass through the port when their portions are disengaged, for core removal, by first withdrawing the hub and, for core replacement, by inserting the hub with fins in predetermined positions in the chamber.

[451 Aug. 12, 1975 United States Patet [191 Joyce [54] ZONAL CENTRIFUGEROTORS 825,721 7/1906 Hartmann....

1,643,441 9/ l 927 Blanchard [75] Inventor: John E. Joyce, Weymouth,Mass. 3,047,216 7/1962 [73] Assignee: International Equipment Company, gfi l t l cese a...... Needham Heights, Mass. 3,350,002 10/1967 Mar. 24,1970 Appl. No.: 22,358

22 Filed:

Primary ExaminerGeorge H. Krizmanich Related US. Application Data [63]Continuation-in-part of Ser. No. 755,003, Aug. 23,

ABSTRACT Zonal centrifuge rotors are disclosed which have a core thatcannot be passed into the chamber of the bowl through an axial port inits top wall that is prefer- 1968, abandoned.

ably an integral part of a bowl. Each core includes a hub and finshaving detachably engaged portions and dimensioned to pass through theport when their portions are disengaged, for core removal, by firstwithdrawing the hub and, for core replacement, by insert- 24 4 30 4 My 3wm M 8 M nn a3 M423 W32 0 m M WBB mmr ""3 .e ms QLM d S M U h F NUQ QUUU [56] References Cited UNITED STATES PATENTS ing the hub with fins inpredetermined positions in the chamber.

233/33 233/44 16 Claims, 7 Drawing Figures 362,449 5/1887Koelkebeck.................i........ 496120 4/1893 ZONAL CENTRIFUGEROTORS The present invention relates to zonal centrifuge rotors, andparticularly to such rotors that, for their size and weight, are adaptedto be rotated at substantially higher speeds than presently availablezonal rotors of approximately the same size and weight. The presentapplication is a continuation-inpart of my co-pending application Ser.No. 755,003, filed Aug. 23, 1968 and now abandoned.

In centrifuges, one of the factors limiting speeds is the strength ofthe rotor being used. Where rotor strength is achieved with a weightincrease, the added weight becomes a limiting factor. The problem ofrotor strength is particularly troublesome in the zonal field as zonalrotors have covers closing the bowl and include removable cores dividingthe bowl into compartments into which and from which liquids aredelivered and removed through axial distributing means.

Because of the necessity of zonal rotors having detachable covers topermit core insertions and removals, zonal rotors have not hadsufficient strength to avoid undesirable speed limitations. The primaryobjective of the present invention is to provide zonal centrifuge rotorsconstructions that are free of these speed-limiting features.

In accordance with the invention this general objective is attained byproviding a zonal centrifuge rotor including a bowl having a chamber inwhich the core is located and an axial port in its top wall incommunication therewith, with the top wall being preferably an integralpart of the bowl. The removable core consists of an axial hub and finsincluding detachably engaged portions providing an operative finposition in which the chamber is divided intocompartments. The assembledcore cannot be passed through the port when the portions are engaged butthe hub and fins are dimensioned to pass therethrough when the portionsare disengaged. Such disengagement is effected to permit core removal bywithdrawing the hub and, in the case of core replacement, reengagementis effected by inserting the hub through the port with the fins inpredetermined positions in the chamber.

Because the strength of a rotor bowl increases as the diameter of itsopening decreases and because the invention also provides cores each ofwhich may be so disassembled as to permit its hub to be removed from thebowl chamber through the port before the fins and reassembled within thechamber by reverse procedure, zonal centrifuge rotors are provided thatare well adapted for use at substantially higher speeds than hashitherto been possible.

Another objective of the invention is to provide cores in each of whichthe interengageable portions of the hub and fins include cam partsoperable to force the fins into their operative positions during theentry of the hub into the chamber.

Yet another objective is to provide a core construction in which theinterengageable portions of the hubs and fins are vertical channels inthe core dimensioned to slidably receive the inner edges of the fins,preferably with at least part of each channel and each inner edge beinginclined to provide cam surfaces, and preferably with the fins becomingcompletely separated from the hub as the hub is removed from thechamber.

Another objective of the invention is to provide the bowls with meanspositively establishing the predetermined positions of fins that aredetached from their hubs.

Yet another objective of the invention is to provide the cor es with finconstructions including sectioned fins and special shapes to enable theport dimensions to be reduced to a satisfactory extent.

Where the fins have passages extending from their inner edges to theirouter edges for communication with radial ports of hub passages when thecore is assembled, the proximate ends of the passages open through thecam parts. Another objective is to ensure, where fins are verticallysectioned, a seal between the proximate ends of the sections of the finpassages in a like manner by providing the proximate edges of the finsections with coacting cam parts through which such proximate passageends open.

In the accompanying drawings, there is shown an illustrative embodimentof the invention from which these and other of the objectives, novelfeatures, and advantages will be readily apparent.

In the drawings:

FIG. 1 is a vertical section of a zonal centrifuge rotor in accordancewith the invention;

FIG. 2 is a section taken approximately along the indicated lines 22 ofFIG. 1;

FIG. 3 is a fragmentary, perspective view of the core engaging portionat the bottom of the bowl;

FIG. 4 is a top view of the hub of the core;

FIG. 5 is a perspective view, on a reduced scale, of a fin in accordancewith another embodiment of the invention;

FIG. 6 is a fragmentary bottom view of the bowl showing the means bywhich it is secured to the drive spindle of a centrifuge; and

FIG. 7 is a fragmentary vertical section, on an increased scale, of thethreaded connection between the port and the cap therefor.

In the embodiment of the invention illustrated by the drawings, the bowlof a zonal centrifuge rotor is indicated at 10 and includes an integraltop wall 11 having a central boss through which the port 12 extends andwhich defines an upwardly disposed rim 13. The port 12 opens downwardlyinto the chamber 14 in axial alignment with a centering boss 15 having adiametrically disposed rib or key 16 and a series of radial slots 17.The bottom of the bowl 10 has a boss 18 for connection with the drive ofthe centrifuge.

The rim 13 has an annular groove for the sealing ring 19 and the port 12has threads 20 adjacent its upper end. A cap, generally indicated at 21,includes an axial cylindrical portion 22 provided with threads 23adjacent its upper end for locking engagement with the threads 20. Aswill be noted from FIG. 7 the threads20 and 23 have contact surfacesonly in horizontal planes. The cap 21 is also provided with an annulargroove 24 in the undersurface of its marginal flange 25 receiving withinit the rim 13 when the cap 21 is secured. It is preferred thatthe topwall have an annular channel 11A to effect an increase in the axialextent of the rim 13 to enable the overlap of the cap 21 relativethereto to be correspondingly increased. The cap 21 also includes anaxial bore 26 having a counterbore 27 in its outer or upper surface.

The centrifuge core consists of a hub, gen erally indicated at 28',having angularly disposed flat sides 29 which are shown as upwardly andinwardly inclined and as terminating in a shoulder 30 above which thereis a 3 cylindrical, axial neck 31. In the bottom of the hub 28, there isan axial recess 32 dimensioned to receive the centering boss andprovided with a transverse slot 1 or keyway 33 providing a positivehub-to-bowl connection when the key 16 is entrant thereof.

The height of the hub 28 is equal to the bowl depth and its neck 31 isdimensioned to extend through the bore 26. The neck 31 has verticallyspaced grooves for sealing rings 34 and in its upper end, there is asocket 35 with a central boss having an axial bore 36 extending throughthe neck 31 and it includes radial ports 37, one for each flat side 29and extending across the upper surface of the shoulder 30. Verticalbores 38 extend downwardly through the neck and hub and each has aradial outlet 39 in the appropriate one of the channels 40 extendingvertically along the junction between adjacent sides 29 of the hub 28.

The lower sealing ring 34 is a seal for the bore 26 while the uppersealing ring 34 is entrant of an annular detent groove 41 in a generallyindicated cap 42, the cap 42 having relief ports 43 opening into thegroove 41. A manually engageable knob 44 is connected to the cap 42 by aball bearing unit 45 thereby enabling the cap 42 to be gripped andpulled from the neck 31 while the centrifuge is in operation.

Fins 46, when attached to the hub 28 within the bowl chamber 14, dividethe chamber 14 into compartments 47, see FIG. 2. Each fin 46 has itsinner edge dimensioned to slidably fit a hub channel 40 and with itsbottom part entrant of and held by a slot 17 in the boss 15. The innerfin edges and the channels 40 are complemental in shape with each innerfin edge having an intermediate outwardly and upwardly inclined surfacedefining a cam part 48 through which one end of a passage 49 opens withthe other end opening through a nipple 50 in its outer edge into agroove 51 which is of maximum depth when it extends between thecompartments 47 and which more or less vanishes in each compartment asshown in FIG. 2. The inner edge of each fin 46, below its cam part 48,tapers downwardly and inwardly as at 52. Each cam part 48 is engageablewith a like intermediate cam part 53 with which each hub channel 40 isprovided and through which a radial outlet 39 opens.

With a core in accordance with the invention, each fin 46 may bepositioned in the chamber 14 in a slot 17 thereby to be held upright ina predetermined position. The hub 28 may then be inserted through theport 12 with the inner edges of the fins 46 entering the hub channels40. As the hub 28 is bottomed, the cam parts 48 and 53 coact to forcethe fins 46 outwardly into their operative, compartment definingrelationship with the engaged cam parts providing a tight sea] at thejunction of the outlets 39 and the passages 49. If desired, each fin campart 48 may have an annular recess surrounding the inner end of itspassage for a sealing ring 54, see FIG. 5. When the core is to beremoved, the cap 21 is first detached and the hub 28 is then lifted freewith the fins 46 becoming detached so that each may subsequently beremoved.

It will be noted that each fin 46 is shown as having a notch 55 in itsupper edge which increases in depth towards the inner end thereof andthat the upper and lower ends of the outer edge of the fins are roundedto conform to the curvature at the top and bottom of the chamber 14 andthat between their rounded ends, the outer edges are shown as straight.When a fin 46 is to be removed the notch 55 permits the rear of that finto be raised to clear the boss 15 so that it then may be removed throughthe port 12.

Where further reduction in the diameter of the rotor port relative tothe diameter of the bowl chamber is wanted, the fins may be made insections as is illustrated in FIG. 5. The fin shown in FIG. 5 is similarto that previously described with the reference numerals for thecorresponding parts being distinguished by the suffix addition A. Thefin 46A includes vertically divid'ed inner and outer sections 56 and 57whose proximate edges abut and include a tongue and groove portions 56Aand 57A, respectively, and intermediate cam parts 58 and 59 throughwhich the proximate ends of the passage 49A open and by which they aresealed together when the fins 46A are operatively positioned within therotor.

It has been noted that where the rotor bowl has an integral top wall,the rotor strength increases as the diameter of its axial port 12decreases. No substantial advantage results if the port diameter is muchin excess of 55% of the inside diameter of the bowl and the constructionand assembly of the core becomes a problem if the diameter of the port12 is much less than 25% of said inside diameter. By way of example, arotor whose port 12 was 51.6% of the inside diameter of the chamber andhaving a capacity of 7.5% greater than that of a comparable rotor iscapable of operating at a 16.5% higher speed than the rotor of standardconfiguration thus affording a 36% increase in centrifuge force and anincrease of 46% in operating efficiency.

I claim:

1. A zonal centrifuge rotor including a bowl having a chamber and anintegral top wall having an axial port in communication with saidchamber and of a diameter substantially smaller than that of thechamber, a cap for said port and detachably secured thereto, and aremovable core within said chamber, said core and said bowl includingportions detachably interengaged to ensure they rotate together, saidcore including an axial first part in the form of a hub and a pluralityof second parts, each in the form of a fin having upper, lower, innerand outer edges, said inner edges extending into the space directlybelow the port and at least a part of the other edges abut the innersurfaces of the bowl to establish compartments, means inthe bottom ofsaid chamber receiving and slidably holding each second part in apredetermined radial position, said hub and fins including detachablyengaged sets of connecting portions disengageable by upward movement ofthe hub relative to the fins, said hub and each of said fins dimensionedfor passage through said port, said connecting portions renegageable ondownward movement of the hub with the fins in said radial position.

2. The zonal rotor of claim 1 in which the detachably engaged connectingportions include means operable to effect radial movement of the finsinto their compartment-establishing positions as the hub is insertedinto its core-establishing position within the chamber.

3. The zonal rotor of claim 1 in which each of the lengthwise portionsof the hub are channels and the lengthwise portion of each fin is in itsrear edge and the channels and the rear fin edges are inclineddownwardly and inwardly inclined cam parts that coact on the assembly ofthe core within the chamber to efi'ect the compartment-establishing finpositions.

4. The zonal rotor of claim 3 in which the hub has a passage openingradially through the cam part of each channel and each fin has a passageopening at one end through the cam part of its rear edge and at theother end through its front edge, the proximate ends of the passagesbeing in communication when the fins are in theircompartment-establishing positions.

5. The zonal rotor of claim 1 in which the portion of the bowl that isengaged by a portion of the core to ensure their rotation together is anaxial boss on the bottom of the bowl, there are radial channels in theboss, the hub has a recess receiving the boss, each fin includes aninwardly disposed portion adjacent the bottom of its inner edgeextending under the hub and into one of the channels of the boss toslidably support that fin, the detachably engaged portions includecoacting cam parts disposed, when slidably engaged, to effect radialmovement of the fins into their compartmentestablishing positions.

6. The zonal rotor of claim 1 in which the bowl includes an axial bossin the chamber, the fin holding means are radial outwardly openingchannels in the boss with their closed ends close to the bowl axis, theupper edge of each fin has a notch increasing in depth towards the innerend thereof, and the outer ends of the upper and lower edges having arounded mergence with the outer edge which are in engagement withcorresponding portions of the inner surface of the bowl and which, withthe notch, enable the inner part of each fin to be raised to clear theradial channel by which it is held and then withdrawn from the chamber.

7. The zonal rotor of claim 1 in which each fin includes inner and outersections and means whose proximate edges abut and include lengthwisetongue and groove portions slidably joining the fin sections together toenable them to be interconnected or separated while within the chamber.

8. The zonal rotor of claim 4 in which each fin includes inner and outersections whose proximate edges include tongue and groove portions andintermediate coacting cam parts through which the fin passages open.

9. A core for a zonal centrifuge rotor bowl having a top wall overlyingthe core-receiving chamber and provided with an axial port, the corecomprising a hub and fins, said hub and fins including detachablyengaged sets of connecting portions disengageable by upward movement ofthe hub relative to the fins and reengageable on downward movement ofthe hub with the fins in predetermined positions within the bowl, saidhub including one set of said connecting portions and each of said finsincluding an appropriate one of said other set of connecting portions,the detachably engaged portions enabling the fins to move radiallyoutwardly relative to the hub and both sets of connecting portionsincluding parts that become engaged on such movement of the hub, saidparts of at least one set being cam parts disposed then to effect suchoutward movement of the fins.

10. The core of claim 9 in which each fin has top, bottom, inner andouter edges and the connecting portions of the hub channels and theconnecting portions of the fins are their rear edges, and the parts thatbecome engaged on downward movement of the core are both cam parts, eachof the cam parts of the hub is an intermediate upwardly and outwardlyinclined portion of each channel and the cam part of each find is anintermediate and correspondingly inclined portion of the rear edgethereof.

11. The core of claim 9 in which each fin includes inner and outersections whose proximate edges abut and which include lengthwise tongueand groove portions.

12. The core of claim 10 in which the hub has passages opening radiallythrough each cam part and each fin has a passage opening at one endthrough its cam part and at the other end through its outer edge, and inoperational alignment with the appropriate radial opening on downwardmovement of the hub relative to the fins to a predetermined extent.

13. The core of claim 12 in which each fin includes inner and outersections whose proximate edges abut and include lengthwise tongue andgroove portions and intermediate cam parts through which the finpassages open.

14. A fin for a zonal rotor core having a hub provided with vertical,fin-receiving open-ended slots the lower portions of which are inwardlyand downwardly inclined cam surfaces and radial ports opening throughits cam surfaces, said fin having upper, lower, inner and outer edges,said inner edge dimensioned to fit a hub channel and the lower portionthereof and being downwardly inclined to define a cam,- said fin alsohaving a passage effecting communication between the cam of its inneredge and the central portion of its outer edge.

15. The fin of claim 14 in which the upper edge has a notch increasingin depth towards its inner edge and the outer end of the upper and loweredges have a rounded mergence with the outer edge.

16. The fin of claim 15, the fin including inner and outer sections, theproximate edges including lengthwise slidably engageable tongue andgroove portions.

1. A zonal centrifuge rotor including a bowl having a chamber and anintegral top wall having an axial port in communication with saidchamber and of a diameter substantially smaller than that of thechamber, a cap for said port and detachably secured thereto, and aremovable core within said chamber, said core and said bowl includingportions detachably interengaged to ensure they rotate together, saidcore including an axial first part in the form of a hub and a pluralityof second parts, each in the form of a fin having upper, lower, innerand outer edges, said inner edges extending into the space directlybelow the port and at least a part of the other edges abut the innersurfaces of the bowl to establish compartments, means in the bottom ofsaid chamber receiving and slidably holding each second part in apredetermined radial position, said hub and fins including detachablyengaged sets of connecting portions disengageable by upward movement ofthe hub relative to the fins, said hub and each of said fins dimensionedfor passage through said port, said connecting portions renegageable ondownward movement of the hub with the fins in said radial position. 2.The zonal rotor of claim 1 in which the detachably engaged connectingportions include means operable to effect radial movement of the finsinto their compartment-establishing positions as the hub is insertedinto its core-establishing position within the chamber.
 3. The zonalrotor of claim 1 in which each of the lengthwise portions of the hub arechannels and the lengthwise portion of each fin is in its rear edge andthe channels and the rear fin edges are inclined downwardly and inwardlyinclined cam parts that coact on the assembly of the core within thechamber to effect the compartment-establishing fin positions.
 4. Thezonal rotor of claim 3 in which the hub has a passage opening radiallythrough the cam part of each channel and each fin has a passage openingat one end through the cam part of its rear edge and at the other endthrough its front edge, the proximate ends of the passages being incommunication when the fins are in their compartment-establishingpositions.
 5. The zonal rotor of claim 1 in which the portion of thebowl that is engaged by a portion of the core to ensure their rotationtogether is an axial boss on the bottom of the bowl, there are radialchannels in the boss, the hub has a recess receiving the boss, each finincludes an inwardly disposed portion adjacent the bottom of its inneredge extending under the hub and into one of the channels of the boss toslidably support that fin, the detachably engaged portions includecoacting cam parts disposed, when slidably engaged, to effect radialmovement of the fins into their compartment-establishing positions. 6.The zonal rotor of claim 1 in which the bowl includes an axial boss inthe chamber, the fin holding means are radial outwardly opening channelsin the boss with their closed ends close to the bowl axis, the upperedge of each fin has a notch iNcreasing in depth towards the inner endthereof, and the outer ends of the upper and lower edges having arounded mergence with the outer edge which are in engagement withcorresponding portions of the inner surface of the bowl and which, withthe notch, enable the inner part of each fin to be raised to clear theradial channel by which it is held and then withdrawn from the chamber.7. The zonal rotor of claim 1 in which each fin includes inner and outersections and means whose proximate edges abut and include lengthwisetongue and groove portions slidably joining the fin sections together toenable them to be interconnected or separated while within the chamber.8. The zonal rotor of claim 4 in which each fin includes inner and outersections whose proximate edges include tongue and groove portions andintermediate coacting cam parts through which the fin passages open. 9.A core for a zonal centrifuge rotor bowl having a top wall overlying thecore-receiving chamber and provided with an axial port, the corecomprising a hub and fins, said hub and fins including detachablyengaged sets of connecting portions disengageable by upward movement ofthe hub relative to the fins and reengageable on downward movement ofthe hub with the fins in predetermined positions within the bowl, saidhub including one set of said connecting portions and each of said finsincluding an appropriate one of said other set of connecting portions,the detachably engaged portions enabling the fins to move radiallyoutwardly relative to the hub and both sets of connecting portionsincluding parts that become engaged on such movement of the hub, saidparts of at least one set being cam parts disposed then to effect suchoutward movement of the fins.
 10. The core of claim 9 in which each finhas top, bottom, inner and outer edges and the connecting portions ofthe hub channels and the connecting portions of the fins are their rearedges, and the parts that become engaged on downward movement of thecore are both cam parts, each of the cam parts of the hub is anintermediate upwardly and outwardly inclined portion of each channel andthe cam part of each find is an intermediate and correspondinglyinclined portion of the rear edge thereof.
 11. The core of claim 9 inwhich each fin includes inner and outer sections whose proximate edgesabut and which include lengthwise tongue and groove portions.
 12. Thecore of claim 10 in which the hub has passages opening radially througheach cam part and each fin has a passage opening at one end through itscam part and at the other end through its outer edge, and in operationalalignment with the appropriate radial opening on downward movement ofthe hub relative to the fins to a predetermined extent.
 13. The core ofclaim 12 in which each fin includes inner and outer sections whoseproximate edges abut and include lengthwise tongue and groove portionsand intermediate cam parts through which the fin passages open.
 14. Afin for a zonal rotor core having a hub provided with vertical,fin-receiving open-ended slots the lower portions of which are inwardlyand downwardly inclined cam surfaces and radial ports opening throughits cam surfaces, said fin having upper, lower, inner and outer edges,said inner edge dimensioned to fit a hub channel and the lower portionthereof and being downwardly inclined to define a cam, said fin alsohaving a passage effecting communication between the cam of its inneredge and the central portion of its outer edge.
 15. The fin of claim 14in which the upper edge has a notch increasing in depth towards itsinner edge and the outer end of the upper and lower edges have a roundedmergence with the outer edge.
 16. The fin of claim 15, the fin includinginner and outer sections, the proximate edges including lengthwiseslidably engageable tongue and groove portions.